Greetings,

I am trying to create an outbound and an inbound TCP connection on 2 separate sockets (5000 out, 5001 in). Nominally this is for a connection with a Node-Red flow. I have also tried to test the same code between two S7-1212 CPU's (duplicated and inverted).

When I go PLC to PLC,the outbound TCON fails with 16#80C5 on both sides. When I run the version to connect with the node red flow, I get a good outbound connection (as indicated in the "error" and in node red) but the inbound (TCON 2) fails with 16#80A2. This later version is the one i include here.

Ive been looking in the forums, and documentation all day and trying different configurations with no luck. It acts like node red is hitting a firewall in the S7-1200. I thought however that the second TCON (port 5001) would open that. Either way I am at wits end. I need a bi-directional TCP connection somehow.

It would be greatly appreciated if someone could take a look at my code and point out my error?

Thanks for your attention on this. The original attached project is for the connection to Node Red (1 PLC, port 5000 (TCON_1) outgoing from PLC, port 5001 (TCON_2) incoming). To avoid confusion I will be addressing only the version attached that is supposed to talk to Node Red TCP.

Here are screenshots of pretty much everything from the TCON code to the configuration to the result. This is the version that gives the status error 16#80A2 on the passive (incoming) port 5001. As for the active port (5000) that connects and transmits flawlessly to Node Red.

This is confusing.
1) What is the justification of starting this new topic
            original: S7-1200 Open TCP problem (TCON)

2) The program you shared is incomplete.

Have a look at the library:
Libraries for Communication for SIMATIC Controllers

Within the library is a template for TCP communication that has all the ins and outs. This may be of help to you quicker than a tutor session.

Some hints:

1. It is important to know which partner initiates the link. 
2. Simulating communication between two PLCs from the same project is possible.
3. PLCSIM cannot link to 'outside' devices.
4. In-software help gives a list of ports that may be used. 5001 is best avoided.

A bit quick on the trigger in the first reply.

The parameters you pointed out are hard coded in the "TxRxBlock" DB. 1200 - 1200 (project archive *0.4) one plc is 192.168.30.20 the other is 192.168.30.25. To Node red (project *0.3), the PLC is 192.168.30.20 and the machine running node red is 192.168.30.50.

I have the library you pointed out. I took a look at LCOM and the documentation. That is a whole lot more complicated than what Im trying to do here. Also the documentation seems to reference to the 300-400 series. I have used LMQTT from this library and Node Red with success though.

Just to be clearer I am on live hardware on both project examples. Going 1200 - 1200 nothing is received on either end. Going 1200 - Node Red I am receiving from the 1200 just fine. Problem is the 1200 will not receive anything.

The whole thing acts like the 1200 is refusing incoming connections.

After a quick inspection of your code:
Have a look at the documentation. The structure currently used for 'CONNECT' is the wrong type. You need to use the IP4 one. See the documentation for more.

When using bi-directional communication for one port, use either TSEND_C or TRCV_C. using both is not needed. It is possible to combine 
a) TSEND_C and TRCV     or
b) TSEND and TRCV_C

The *_C instruction handles the connection.

For uni-directional, this does not apply. But in that case another port number is used.

Duris,

Thank you but what you sent also did not work. Again it seemed as if I hit some sort of firewall trying to come in to the other PLC. For the time being I abandoned trying to communicate between the 2 PLC's as my real goal is 1200 - Node Red.